Bidirectional amplifying architecture with twin pulses for laser fusion facilities

A novel method to amplify laser pulses in inertial confinement fusion (ICF) facilities is presented, in which twin pulses are employed to propagate along the amplifier in opposite directions. The resulting bidirectional propagation provides a substantially higher extraction efficiency of the amplifier than the conventional multipass architecture for an equal B limit, while keeping the laser fluence at a low level that is beneficial to system reliability and stability. It is shown that an extraction efficiency of ∼61% is achievable under a laser fluence of 10 J cm^-2 (1ω, one pulse) in an 18-slab amplifier with the bidirectional amplifying design (slab thickness: 4 cm, small signal gain coefficient: 0.0525 cm^-1), while the extraction efficiency is only ∼40% under a fluence of 13 J cm^-2 (1ω) for the conventional multipass architecture.